1. Field of the Invention
The present invention relates to catalysts, to methods of making catalysts, to methods of using catalysts, to methods of polymerizing, and to polymers made with such catalysts. In another aspect, the present invention relates to polyolefin catalysts, to methods of making such catalysts, to methods of using such catalysts, to polyolefin polymerization, and to polyolefins. In even another aspect, the present invention relates to Ziegler-Natta catalysts, to methods of making such catalysts, to methods of using such catalysts, to polyolefin polymerization, and to polyolefins.
2. Description of the Related Art
Having been around since the early 1950""s, Ziegler-type polyolefin catalysts, their general methods of making, and subsequent use, are well known in the polymerization art.
However, while much is known about Ziegler-type catalysts, there is a constant search for improvements in their polymer yield, catalyst life, catalyst activity, and in their ability to produce polyolefins having certain properties.
U.S. Pat. No. 4,255,544, issued Mar. 10, 1981 to Kimura et al., discloses a process for polymerization of ethylene utilizing a catalyst comprising (A) the reaction product of a magnesium compound and titanium halide, and (B) an organic aluminum compound, wherein Component A is prepared by reacting magnesium dialkoxide with a hologen-containing silicon compound and an alcohol to provide a solid material and then reacting the solid material with titanium halide in the presence of an alkoxy-containing silicon compound.
U.S. Pat. No. 4,914,069, issued Apr. 3, 1990 to Job et al., discloses the preparation of an olefin polymerization catalyst component having improved activity and selectivity, which are prepared by (a) halogenating a magnesium compound containing at least one aryloxy, alkyl or carbonate or alkloxy group with a first halide of tetravalent titanium and a first electron donor; (b) contacting the resulting product with a second halide of tetravalent titanium; and (c) washing a resulting treated halogenated product with an inert hydrocarbon liquid. In the process, a second electron donor is used in step (a) or (b), and that the product of step (b) is contacted in a step (b2) with a third halide of tetravalent titanium at a temperature of 40xc2x0 C. to 140xc2x0 C. and thereafter the treated product is washed in step (c).
U.S. Pat. No. 5,155,187, issued Oct. 13, 1992 to Shelly, discloses a polymerization method utilizing a catalyst which is the reaction product generally of a silicon-containing compound, a magnesiumdialkyl, an alcohol, a halide-containing metal compound, an aluminum alkoxide, and a second halide-containing metal compound.
U.S. Pat. No. 5,610,246, issued Mar. 11, 1997 to Buehler et al., discloses a process for polymerizing propylene using a silica-supported catalyst. The catalyst comprises the product obtained by contacting silica, in random order, with (1) at least one hydrocarbon soluble magnesium-containing compound; and (2) a first modifying compound selected from the group consisting of silicon halides, boron halides, aluminum halides and mixtures thereof followed by a second specified modifying compound.
U.S. Pat. No. 5,631,334, issued May 20, 1997 to Zandona, disclose a process for the manufacture of a catalytic solid for the (co)polymerization of at least one olefin, comprising the coprecipitate magnesium and of at least one transition metal.
However, in spite of these advancements in the prior art, none of these prior art references disclose or suggest that increasing the amount of titanation agent in the second titanation step in the process of making the catalyst will increase the MWD of the resultant polyolefin produced with the catalyst.
Thus, there is a need in the art for a polyolefin catalyst.
There is another need in the art for a method of making a polyolefin catalyst.
There is even another need in the art for a method of polymerizing olefins.
There is still another need in the art for polyolefins of broader MWD.
There is yet another need in the art for a polyolefin catalyst allowing for production of polyolefins of increasing MWD, with a catalyst that also has high activity and excellent fluff morphology.
These and other needs in the art will become apparent to those of skill in the art upon review of this specification, including its drawings and claims.
It is an object of the present invention to provide for a polyolefin catalyst.
It is another object of the present invention to provide for a method of making a polyolefin catalyst.
It is even another object of the present invention to provide for a method of polymerizing olefins.
It is still another object of the present invention to provide for polyolefins of broader MWD.
It is yet another object of the present invention to provide for a polyolefin catalyst allowing for production of polyolefins of various MWD, with a catalyst that also has high activity and excellent fluff morphology.
One embodiment of the present invention provides a catalyst component produced by a process comprising: a) contacting a soluble magnesium dialkoxide compound of the general formula Mg(ORxe2x80x3)2 with a halogenating agent capable of exchanging one halogen for one alkoxide to form a reaction product A, where Rxe2x80x3 is a hydrocarbyl or substituted hydrocarbyl having from 1 to 20 carbon atoms; b) contacting reaction product A with a first halogenating/titanating agent to form reaction product B; and c) contacting reaction product B with a second halogenating/titanating agent to form a catalyst component. Generally, the second halogenating/titanating agent comprises titanium tetrachloride, and the second halogenating/titanating step comprises a ratio of titanium to magnesium in a range of about 0.1 to 5. Preferably, the second halogenating/titanating step comprises a ratio of titanium to magnesium of about 2.0.
Another embodiment of the present invention provides a polyolefin catalyst produced by a process generally comprising: a) contacting a catalyst component of invention together with an organoaluminum agent. The catalyst component is produced by a process comprising i) contacting a magnesium dialkoxide compound of the general formula Mg(ORxe2x80x3)2 with a halogenating agent capable of exchanging one halogen for one alkoxide to form a reaction product A, where Rxe2x80x3 is a hydrocarbyl or substituted hydrocarbyl having from 1 to 20 carbon atoms; ii) contacting reaction product A with a first halogenating/titanating agent to form reaction product B; and iii) contacting reaction product B with a second halogenating/titanating agent to form a catalyst component. The amount of second halogenating/titanating agent utilized is determined by the desired molecular weight distribution of the polymer to be produced utilizing the catalyst. Generally, the second halogenating/titanating agent comprises titanium tetrachloride, and the second halogenating/titanating step comprises a ratio of titanium to magnesium in a range of about 0.1 to 5. Preferably, the second halogenating/titanating step comprises a ratio of titanium to magnesium of about 2.0. The catalysts of the invention have a fluff morphology amenable to polymerization production processes, will provide a polyethylene having a molecular weight distribution of at least 5.0, and will provide uniform particle size distributions with low levels of particles of less than about 125 microns. The activity of the catalyst is dependent upon the polymerization conditions. Generally the catalyst will have an activity of at least 6,000 gPE/g catalyst, but the activity can also be greater than 100,000 gPE/g catalyst.
Even another embodiment of the present invention provides a polyolefin polymer produced by a process comprising: a) contacting one or more xcex1-olefin monomers together in the presence of a catalyst of the invention, under polymerization conditions; and b) extracting polyolefin polymer. Generally the monomers are ethylene monomers and the polymer is polyethylene.
Still another embodiment of the present invention provides a catalyst system comprising a catalyst of the invention and an inert support. Generally the inert support is a magnesium compound.
Yet another embodiment of the present invention provides a process for forming a catalyst component. Generally the catalyst component of the invention is produced by a process comprising: i) contacting a magnesium dialkoxide compound of the general formula Mg(ORxe2x80x3)2 with a halogenating agent capable of exchanging one halogen for one alkoxide to form a reaction product xe2x80x9cAxe2x80x9d, where Rxe2x80x3 is a hydrocarbyl or substituted hydrocarbyl having from 1 to 20 carbon atoms; ii) contacting reaction product xe2x80x9cAxe2x80x9d with a first halogenating/titanating agent to form reaction product xe2x80x9cBxe2x80x9d; iii) contacting reaction product xe2x80x9cBxe2x80x9d with a second halogenating/titanating agent to form a catalyst component.
Even still another embodiment of the present invention provides a process for making a catalyst for use in making a polyolefin of a desired molecular weight distribution (xe2x80x9cMWDxe2x80x9d). Generally the method comprises the steps of: a) contacting a catalyst component of the invention together with an organoaluminum agent.
Still even another embodiment of the present invention provides a process for xcex1-olefin polymerization to provide a polyolefin of a desired molecular weight distribution (xe2x80x9cMWDxe2x80x9d). Generally the method comprises the steps of: a) contacting one or more xcex1-olefin monomers together in the presence of a catalyst of the invention, under polymerization conditions; and b) extracting polyolefin polymer. Preferably the monomers are ethylene and the polymer is polyethylene.
These and other objects of the present invention will become apparent to those of skill in the art upon review of this specification, including its drawings and claims.